An exemplary packaging machine can be seen in DE 2 123 133, incorporated herein by reference. Such a packaging machine has a frame having two frame parts arranged parallel to one another in the longitudinal direction. At one end of the two frame parts chain wheels are provided in each case, via which run two transport chains in the form of continuous chains. The individual chain links of the transport chains are equipped with clamps which hold a length of packaging material, such as a foil, at the edges. When the chain links come into engagement with the chain wheels, the clamps open, so the length of packaging material is inserted into the clamps. When the chain links are released from the chain wheels, the clamps close and the length of packaging material is held in a tensioned state between the transport chains. The chain wheels are in each case cantilevered on an axle. Between the chain wheels a foil guide drum for the length of packaging material is supported as freely rotatable about an axle. At the other end of the two frame parts further chain wheels are provided, which serve to open the clamps again by engaging in the transport chains, so the length of packaging material is released from the clamps. Various working stations are arranged along the frame. During transport of the length of packaging material through the working stations high precision of the forward feeds of both chains is required, in order to achieve as low forward feed tolerances as possible during successive operating cycles. Higher tolerances require more packaging material and cause increased costs. The transport chains have limited stability, however, and are elastically stretched like a spring under load. In particular with longer plants of more than approximately 10 meters in transport length, this stretching property has a marked effect on the precision of the transport distance as the load increases, owing to the length, and higher driving power results in even greater stretching. The relative stretching with greater length of the plant simultaneously gives rise to higher amounts of stretching, which cause practically over-proportionately higher tolerances. Additionally, the fluctuations can come out differently on the two transport chains and therefore cause distortions of the length of packaging, which, depending on the type of packaging material, can even lead to tearing of the length of material.